Readers who actually click through though, might be surprised to learn what the “edge” consists of: A study by researchers at Western Michigan University found that the KIPP network “benefits from significant private funding and student attrition.” Students receive more than $5,000 a year per pupil through private donations on top of regular sources of public funding; and the roughly 15 percent of KIPP students that leave each year are often not replaced. To the extent that these schools ‘outperform’ regular public schools, says the study’s author, “they’re not doing it with the same students, and they’re not doing it with the same dollars.”

This is of course extremely relevant given that KIPP schools are often held up as a model, at least for some people’s kids: “Every low-income school should be measured by how close it gets to that model, where kids go to school from 7:30 a.m. to 5 p.m. and part of the summer,” Newsweek’s Jonathan Alter once explained (7/21/08), though he couldn’t explain why rich kids wouldn’t also benefit from a longer day than most adults spend at work.

It’s interesting how, even while reporting research that should complicate the issue, the Post still leaves undisturbed the thumbnail of the charter network as “known for lifting the achievements of poor children.” (KIPP, for its part, renounced the study, citing “flaws in the data” the paper left unspecified.) … (full text).